Web register mechanism



2 Sheets-Sheet 2 Filed June 14. 1965 FIG-5 FlG-6 -WEB WIDTH 4 6 6 6 3 7H w I I Ill R 4 m n 8 8 M n 0 2 6 6 E Z 7 W 0 F ll u :w 1 m \Q 2 BY WATTORNEYS United States Patent 3,299,777 WEB REGISTER MECHANISM FrancisHunstiger, Parma Heights, Ohio, assignor to Harris-IntertypeCorporation, Cleveland, Ohio, a corporation of Delaware Filed June 14,1965, Ser. No. 463,754 14 Claims. (Cl. 88-24) This application is acontinuation-in-part of application Serial No. 385,441 filed July 27,1964, now abandoned, and assigned to the same assignee.

This invention relates generally to machines for electrophotographicallyprinting onto a moving web of photoconductive material and moreparticularly to an apparatus for registering one or more images on sucha web.

Register make-ready on machines of the general type referred to has beendifficult in the past, particularly on multi-color machines in whichsuccessive colors are to be produced in precise register with eachother. For example, in an electrophotographic machine for printingmultiple colors, a given portion of the web first receives anelectrostatic charge, and then, as it travels to an exposing station,the giVen portion of the web receives a projected image by being exposedto light through transparent areas of a transparency. This dischargesthe lightreceiving areas of this portion of the web. The portion thenpasses into a developing station in which electrostatic toner particlesfor a first color are deposited on and adhere to the areas retaining thecharge, and the adhering particles are fixed thereto. The web portion isthen recharged, exposed and developed to form a second image whichshould be in proper registry with the first. Previously, it has beendifiicult under the circumstances described to determine whether thesecond exposure was in register with the first and to make the necessarycompensating adjustments until after the electrostatic toner particlesfor the second color are deposited and fixed over the first. A registercheck therefore had to await the development of the second color.Naturally, this problem exists at each subsequent unit, and increaseswith an increase in the number of units. This trial and error method toaccomplish registration was time consuming and inconvenient.

It is customary, with existing machines of this type, to make registerchecks of one color to the next while the web is moving through themachine. This is due in part to the fact that the web may have atendency to weave sideways or transversely very slightly during travelalong its normal path. To compensate for this, there has been developeda detecting and leverage system as described in the copendingapplication of Francis Hunstiger and Herbert E. Drake, Serial No.372,503, filed June 4, 1964. This detecting and leverage system causesthe projected image to follow the web laterally or transversely inproper ratio according to the magnification ratio of transparency to theultimate size of print on the web.

In a machine of the type described means are provided for obtainingimage register from one unit to the next in a multi-color machine, or.from the one unit to the web in a single color machine, such registerbeing obtainable while the web is either stationary or absent from themachine. This pre-register enables a substantial reduction in the amountof waste web material such as is common in existing multi-colorelectrophotographic machines, and considerably reduces the amount oftime spent in obtaining register.

The principal object of this invention is to provide a simple andaccurate apparatus for registering a transparency with a web of materialin a machine of the type described while the web is held stationary orbefore it has been threaded through the machine.

3,299,777 Patented Jan. 24, 1967 Another object of the invention is toobtain side register, angular orientation, and sizing of a projectedtransparency image with respect to a predetermined location on acontinuously travelling web of material, such register being obtainablewhile the web is stationary.

Another object of the present invention is the provision of aregistration jig which may be used in conjunction with a multi-colorelectrophotographic apparatus to register the several images in eachunit for accomplishing alignment of the images in each unit with theremaining units.

Other objects and advantages will be apparent from the followingdescription, the accompanying drawings and the appended claims.

In the drawings FIG. 1 is a simplified elevational view of one form ofapparatus embodying the invention, and is taken substantially across thepath of travel of a web of material.

FIG. 2 is a simplified side elevational view of one type of machinewhich may embody the present invention;

FIG. 3 is a view taken generally along the line 33 of FIG. 1, on areduced scale;

FIG. 4 is an enlarged simplified view of a transparency holder which maybe used with the invention;

FIG. 5 is a view similar to FIG. 3, illustrating a second modificationof the invention;

FIG. 6 is a view of a projection table with the registration jig of thepresent invention positioned thereon; and

FIG. 7 is a view from the left of FIG. 6.

Referring now to FIG. 1, a web of photoconductive material 10 is shownbeing fed toward the viewer along the bottom side of a table 11. It isheld in position against the table by vacuum created by an exhaust fan12. The fan evacuates a chamber 13 of the table 11 through perforations14 in the lower surface of the table.

The web 10 is provided with a surface which is adapted to receive anelectrostatic charge on the lower side as viewed in FIG. 1. This chargeis provided over the entire surface of the web It) in the absence oflight. The web is then fed along a path into an area at which certainselected portions of the charged surface are discharged by impingingupon those portions light from a conventional high-intensity,short-duration flashlamp 15. The light passes through condensers 16 andthen through a transparency 17 which has selected image and non-imageareas thereon. These areas may be defined hereinafter as light areasbeing those which transmit light, and shadow areas being those whichprevent transmission of light, however the light areas may correspondeither to the image or non-image areas on the final print at the web 10.For purposes of understanding this invention, it will be assumed thatthe light areas of the transparency discharge the electrostatic chargeon what are to be the non-image areas of the final print. The remainingcharged areas will subsequently receive electrostatic toner particles ofa given electrical potential and will become the image areas of thefinal print.

The light passing through the transparency 17 from the fiashlamp 15enlarges the image on the transparency through a lens 18. In the exampleshown in FIG. 1 the magnification is shown as being in an approximateratio of 10 to 1.

Since it is practically impossible to maintain a travelling web ofmaterial sidewise in its exact theoretical path, a means is provided fordetecting one side edge of the web and translating any slight deviationof the web from its exact theoretical path into a corresponding movementof the lens 18 in the same transverse direction. This is accomplished inthe aforementioned application of Hunstiger and Drake. It should beunderstood, however, that other detecting means may readily accomplishthe same objective, and such detecting means need not act on the 3 edgeof the web. Furthermore, while it is preferred to move the lenstransversely, the principal objective is to move the projected image.Lens movement is simply a convenient and desirable way to accomplishthis.

Very simply shown, the preferred form of detectingor sensing meansincludes a ski 19 which glides over one side edge of the web 10. The skiis fastened to a lever 20 pivoted on a frame member 21 at point 22. Across-link 23 which lies in the plane of the lens 18 (and is thereforeparallel to the plane ofthe web is operatively connected to the lens 18through parallel fiex'ure plates 24 connected at their lower endsapproximately in the plane of the transparency 17 to a projector housing25} The housing 25 is carried by the frame member I The flexure plates24 are shown in FIG. 1 in their neutral or zero position and are capableof movement to the right and left to follow rightward or leftwardmovement of the cross-link 23 in response to movement of the lever 2%The cross=link 23 is urged leftwardly by a spring 26 and rightwardly bythe side edge of the web 10. acting upon the ski 19. Consequently it canbe seen that the spring 26 and the edge of the web 10 oppose each otherand stabilize the ski 19 and the mechanism operated thereby. When theside edge of the web is in its theoreti= cally correct path, the ski 19will be in the position of FIG. 1 and the flexure plates 24 mounting thelens 18 will be in the full-line positions of FIG. 1. A deviation of theweb it) to the left will cause the ski 19 to pivot counterclockwise veryslightly about point 22 under the urging of spring 26. A roller 27carried by the cross-link 23 rides against one side of the lever 20. Theroller 27, upon movement of the lever 20, will permit the cross-link 23to move leftwardly under the urging of the spring 26, and will cause thefiexure plates to move the lens 18 left- Wardly. The amount of leftwardmovement of the lens will be in the same ratio as the magnification ofthe transparency to the web, in this instance, 10:1. Since the lensmovement is only one-tenth of the actual side movement of the web, itwill be seen that the lens 13 will remain sufficiently parallel to theweb so as not to distort the image to be produced on theweb. It will beseen that the mechanism described thus far causes the projected image tomove laterally or transversely in response to similar web movement, sothat any side deviation of the web from its normal path is. compensatedfor by a corresponding side movement of the image.

A problem with previous machines of the general type described has beenthe difiiculty of obtaining initial registration of the transparency 17with respect to the web 10. Registration is required in threedirections. image must be properly sized or magnified onto the web. Toobtain tht proper enlargement ratio, the projector 25 and frame 21 aremoved in knownmanner toward and away from the web 10, asshown by arrow28. Such movement is normally small. If, in movement of the projector25, the image goes slightly out of focus, the lens 18 may be adjustedrelative to the transparency in very small amounts by a lens. focusingmechanism (not shown). Second, the transparency must be angularlyoriented with respect to the web 10. This is accomplished by mountingthe transparency 17 in a transparency holder 2 and adjusting the holderand transparency angularly relative to the projector 25. The details ofsuch adjusting mechanism are shown in the Hunstiger and Drakeapplication previously identified and shown simply in FIG. 4. A pivot 30is provided for a bar.31 against which the holder 29 is urged by meansof a spring 32.. An adjustment screw 33 engaging one edge of the bar 31permits the entire holder 29 and the transparency 17 held thereby topivot about the point 30 in the directions of the arrow 34.

Thirdly, the transparency must be aligned transversely with the web. Thetheoretical side edge of the web is preferably used as a reference pointfor obtaining transverse or lateral registration. Such lateralregistration may be obtained through adjustment of a screw 35 which isFirst, the.

opposed by a spring 36. The spring urges holder 29 into engagement withthe screw 35. Obviously, any type of mechanism can be used to providethe necessary movements of the transparency toward and away from the webfor sizing, angularly with respect to the web to square the transparencytherewith, and laterally with respect to the web for side registration.The mechanism shown in FIG. 4 is for purposes of illustration only.

Previous machines of this general type accomplished these differentregistrations while the web was running. In earlier machines, a firstprint would be made on the web in the desired location at the firstprinting unit or exposing station. Subsequent prints at subsequentexposing stations required these three different registrations to bemade one at a time by running the web, exposing and printing the secondcolor over the first, and checking the resultant print to determine theaccuracy of registration. This trial and error method resulted in wasteof the photoconductive paper.

It has been found further that it is impractical to start and stop theweb to obtain register from one unit to the next. This is due to anumber of factors, perhaps the most important of which is that it isdiificult to run a web in reverse if it overshoots its correct stoppingpoint. Additionally, machines of this type provide for the flashing ofan image onto a web in response to a photocell pick-up of a registermark electrostatically formed by the first unit. This mark triggers theflashlamp at subsequent stations for exposing subsequent images to theweb. For the details of registration and photocell detection, referenceis made to application Serial No. 240,253 filed November 27, 1962. Thusit can be seen that if a first print is to be made and the web is to bestopped at the second exposing station, it must be stopped in an exactrelationship with the first print. It i extremely difficult to line upweb marks longitudinally so that the web is stopped at the exactposition in each station at which the photocell pick-up triggers theflashlamp to make the exposure. Because of these and other problems, ithas been found necessary in the past to effect registration while theweb was travelling through the machine.

This invention relates to apparatus enabling the simple setup of theprojector and the transparency mounted therein with certain machineelements in order to achieve registration between units in a multi-colormachine (or between the only unit and the machine in a single colormachine) without the necessity of running the web through the machinewhile establishing pre-register. It is also possible to obtain suchregistration by use of the apparatus of the present invention without aweb being present in the machine whatsoever. These ends are accomplishedin the FIG. 1 form of the invention by providing the outer surface of aregister slide bar 37 flush with the lower surface of the table 11. Thebar contains register marks 38 as shown in FIG. 3. The marks are shownin the form of cross-lines. The portion of the mark parallel to the sideedge of the web is for obtaining side register while that portionperpendicular thereto is for angular orientation of the image to theweb. The bar 37 is mounted for sliding movement in a groove 39 in thetable 11, which groove is arranged transverse to the web. The bar 37 isheld in its groove 39 by means of straps 40, but is permitted to slidefreely in response to movements of the ski 19 as the web shifts toeither side of a zero or neutral condition of the ski 19. It will benoticed that the bar 37 is arranged to permit passage of the ski 19therethrough in such a fashion as to provide bearing surfaces betweenthe ski l9 and bar 37 which accurately engage the ski but which permitit to move with the lever 21) and frame member 21 whenever they areadjusted toward and away from the Web 149 for sizing. It will be notedthat the register marks 38 on the bar are outside the edges of the web.This is preferred since the difficulty of threading a web through amachine 5. of this type makes it desirable to leave the web in positionfrom one job to the next. By placing these marks beyond the side edgesof the web, register can be obtained Whether the web is present in orabsent from the machine. Corresponding register marks 41 are located onthe transparency 17 in exact registration with an image 42 on thetransparency. The transparency register marks 41 are obtained throughnormal photographic techniques in preparing the transparencies. When thetransparency is mounted in the holder 29 in the first unit and locatedin the projector 25, the operator need merely adjust the transparencyholder 29 in accordance with the techniques previously discussed. He canadjust the projector 25 toward and away from the web to properly sizethe image 42 with the web. He can also provide angular orientation andside registration of the image 42 with respect to that edge of the webwhich is to engage the ski 19. Actual registration is provided byoperating flashlamp at such a high rate that marks 41 appear asnear-continuous light at the table 11. While this is occurring, thetransparency holder is moved according to the visual outof-registerindication of the projected marks 41 relative to marks 38.

It will be seen that if this arrangement is provided at each of theuni-ts in the machine, the roll of web material need only be placed inproper side-to-side location in the machine with its theoretical sideedge aligned with the zero or neutral position of the ski 19 at thefirst exposing station. Since the register marks 38 at each station aremechanically connected through the bar 27, ski 19, lever 20 andcross-link 23 to the projector 25, and since the transparency holder 29can be aligned in the projector to cause coincidence of the transparencyregister marks 41 with the machine register marks 38, it will be seenthat sizing, angular orientation and lateral registration with respectto the ski can be easily obtained. Consequently, since the ski 19 ridesthe edge of the web, such registration will also occur on the paper. Theentire registration is obtainable while the web is stationary. Ifrunning register is desired between units, it will be only for veryminor corrections after preregister has been accomplished.

Referring now to FIG. 2, a multi-color machine is shown including afirst unit 43 and a second unit 44. The web It) travels in the directionof the arrows through a corona charger 45 in which its photoconductivesurface receives an overall electrostatic charge in known fashion. Theweb then passes over a roll 46 and against the under side of vacuumtable 11. At the desired time, the flashlamp in the projector 25 of unit43 exposes the transparency in that unit to the web 10 to dischargethose areas on the charged web surface corresponding to the lighttransmitting areas of the transparency. After exposure, the web thenpasses into a developing and fixing unit 47 which is simply shown ashaving a number of rollers which direct the web to receive liquidelectrostatic toner 48 contained in a pan 49. A roller 50 transfers theliquid toner to the web, and thereafter a roller 51 squeegees excessliquid and causes it to run back into the pan 49. Any form of developingand fixing unit may be utilized, the onedescribed being for purposes ofillustration only. The system may, in fact, use electrostatic powdertoner rather than liquid. After the toner is applied to the web 10, theweb is customarily dried to fix the pigment contained in the toner tothe desired areas to be printed. Upon completion of the first print, theweb passes over a roller 52 and then through a corona charger similar tocharger 45 and then through the unit 44 in the same fashion as in thefirst unit 43.

Referring again to FIG. 3, which is a view taken substantially alonglines 3-3 of FIG. 1, it will be seen that a projected image 53 is shownto be greater in width than the web 10. The purpose of this is to enablethe transparency register marks 41 to extend beyond the side edges ofthe web in order to register with the preferred arrangement of themachine register marks 38. Marks 38 are preferably located outside theedges of the web as stated earlier. The marks 38 are shown as being atthe approximate transverse center-line of the projected image area 53,but obviously can be located anywhere within the projected image area.The register marks may be of any desired shape and are shown simply as apair of cross-lines for purposes of convenience in explanation. Asmentioned earlier, the portion of the cross-lines parallel to the sideedge of the web are for obtaining side registration of the transparencyto the marks and also sizing of the transparency to the web. Theregister marks also contain lines which are perpendicular to the webedges for obtaining angular orientation of the image 42 on thetransparency 17 with the web 10.

Referring now to the modification of the invention shown in FIG. 5,register marks 54 may be placed directly on the table 11'. These marksserve the identical function that is served by the marks 38 of the FIG.3 modification. Since the marks 54 are on a stationary part of themachine, all of the skis 19 in each of the stations are aligned witheach other, and all of the register marks 54 in the various stations areoriginally manufactured and arranged to be in exactly correspondingpositions throughout the machine. Now, with the marks 54 at each stationbeing registered with each other, register of the various skis 19 andlens 18 at the various stations with each other may be obtained and thenthe transparency holders 29 are adjusted to cause the transparencyregister marks to coincide with the register marks 54 on each table 11'.This may be done by providing a gauge screw 55 (see FIGS. 1 and 5),which is threaded through a portion of the machine at each station andadapted for adjustment and locking in adjusted position. A gauge block56 may be provided for insertion between the tips of the gauge screws5'5 and their levers 20. Each gauge block 56 can be held in positionagainst its gauge screw 55 by the fact that the levers 20 are urgedtoward the screws 55 under action of the springs 26. The tips of thescrews 55 are ordinarily adjusted at the factory and need be adjustedfurther only rarely. They provide an adjustable abutment to eliminatethe need for precise manufacturing of a fixed abutment. The tips of thegauge screws 55 at each station will have a definite relationship to theregister marks 54, and consequently, through the use of. the gauge block56, will 'predetermine the positions of the levers and links forcontrolling side movement of the lens 18 in the machine. Although thegauge screws 55 are shown in the FIG. 1 modification, they need not beused with the slide bar 37, but can be so used if desired.

Any type of register mark for obtaining registration may be used. It hasbeen found desirable when using marks on the table 11 of FIG. 5 to formthe marks on a piece of photoconductive paper taped to the table in thelocation where the marks are to be projected. This enables registermarks of any size or shape, or in any position on the transparency to beused. Where the machine is arranged to print webs of different widths,it can be seen that this is highly advantageous since the marks 54should be moved inwardly when a narrower width Web than that shown inFIG. 5 is printed, for example. Where the machine is adapted to handlediiferent width webs, appropriate provisions are made for mounting thepivot 22 of FIG. 1 closer to or further from projector 25 to repositionthe ski 19 according to the actual web width. For different web widths,it will be seen that the FIG. 5 arrangement has certain advantages overthat shown in FIG. 3, since smaller transparencies which cannot beenlarged to reach the marks 38 on both sides of the bar 37 can be used.Necessary provisions are made for relocating the gauge screw 55 at eachunit for diiferent width webs, or several gauge screws may be positionedin each station, one for each width web. Obviously also, perforations 14are arrange to properly handle such various web widths.

Although it is preferred to have the register marks 54 or 38 on oppositeside edges of the web, it is feasible to use one or more such marks onthe same side of the web near the corners of the projected image.

Referring to FIG. 6, a register mark memory device or jig 60 is shownincluding a plate 62 having therein precision drilled holes 64 and 65which receive locating pins 66 and 67 projecting downwardly from thetable 11 toward the projector 25. The projecting pins 66 and 67 .arespaced beyond the edges of the web 10 as shown so they do not interferewith web travel across the table, and pin 66 is located fornon-interfering movement of ski 19. The register mark memory device maybe positioned over the web if desired. Mounted on the plate 62' are apair of spaced clamps 71 and 72 which face towards the projector withthe jig 66 mounted on the table. Each clamp includes a pair of spacedlocking screws 73, 74 and 75, 76 which are threaded into the plat-e 62.Received between the plate 62 and each clamp is a movable arm 84) and 82each carrying a register mark or indicia in the form of cross-lines asindicated in FIG. 6. By tightening down on the screws the position ofthe movable arms 80 and 82 may be fixed relative to the jig and thuswith the pins 66 and 67.

Referring to FIG. 7, each of the arms 80 and 82 is of the same structureand includes a relatively thick support member 84 having at one endthereof a foot 86 to which is attached a relatively thin register markplate 87. In this way, the register mark on the arm is positioned insubstantially the same plane as the web 10. The plate 62 is dimensionedwith respect to the support member 84 and foot 86 so that the plate 87rests either on the web, if one is present, or on the table if no web isin the machine. The plate 62 is shown as being approximately equal inwidth to the width of the web but shorter than the table 11. Itslengthwise dimension (along the direction of web travel) is about onehalf that of the table 11 so that the register marks of the transparencymay be located beyond the image areas. In a preferred form, as shown,the reference marks on the transparency are located in spaced corners ofthe projected pattern and the register mark plates are arranged to placetheir respective register marks in corresponding spaced relation.

In use, the register mark memory device operates to locate the projectedreference marks from the transparency 17. When the transparency ismounted on the holder 29 in the first unit and located in the projector25, the operator need merely adjust the transparency holder 29 inaccordance with the techniques previously discussed to achieve focus,magnification and lateral and angular orientation of the projectedimage.

Once this has been done, arms 80 and 82 are moved in and X and/or Ycoordinate to position the register marks on the register mark plate 87in alignment with the corresponding projected register mark from thetransparency. Once the register mark for each arm is in coincidence withthe corresponding projected registration mark, the locking screws foreach clamp are tightened to fix the position of the movable arms 80 and82.

If a web is in the machine the ski may be positioned against the edge ofthe web so that there is proper lateral alignment of the projected imagewith the projector and then the procedure previously described iscarried out. In the event no web is present in the machine, each unit ofthe machine may be provided with a gauge screw 55 and gauge block 56whose function and operation were previously described so that eachprojection station of each unit of the machine will be in alignment withthe remainder.

Although the apparatus in FIG. 2 shows merely two stations, it isunderstood that the present invention may be utilized with any number ofstations in a multi-color electrophotographic apparatus. Each table 11of each unit of the apparatus includes precision locating pins 66 and 67which are precisely oriented with the theoretical side edge of the webas determined by each gauge screw 55, gauge block 56 and lever 20. Theselocating pins in each station form stationary reference means so thateach projector is properly oriented with respect to the theoretical sideedge of the web. Thus, a roll of web material need only be placed inproper location in the machine with its theoretical side edge alignedwith the zero or neutral position of the ski in each station. In theevent a web is not used, the gauge screws 55 may be used as an alignmentdevice to get the proper lateral registry of the ski and thus theprojector from one unit to the next so that all skis and projectors arein proper lateral registry along the path of web travel.

After proper lateral registry has been accomplished in all units of themachine which in effect places the projector of each unit in alignmentwith each other and with respect to the web, the register memory deviceis assembled in fixed position over the pins in the first unit and inangular, lateral positioning and magnification and focus of the image ofthe first station is accomplished as noted. Thereafter, the registermarks on each register mark plate are brought into alignment withprojected register marks and the respective movable arms of the registermark memory 60 are locked in place by the locking screws. After this hasbeen accomplished the register mark memory device is moved from thefirst unit to the second unit without disturbing the relativeorientation of the register marks on the register mark plates withreference to the drilled holes 64 and 65 on the plate 62.

In the second and remaining stations, the second and remainingtransparencies include register marks. These marks are in the sameprecise orientation with respect to the corresponding image as theregister marks of the first transparency are with respect to the firstimage. Magnification and focus and adjustments are completed, andangular and lateral orientations are made by manipulating thetransparency holder to bring the projected reference marks intocoincidence with the register marks on the register mark plate 67 of thejig 60. Once there is coincidence for the projected register mark of thesecond transparency and the register marks of the register mark memoryor jig 60, the second or subsequent projected image is in properregistry with the first or previous images. This procedure is thencarried out for each of the stations so that each projected image isthus in alignment with the first projected image. As noted previously,the longitudinal alignment along the line of the web is accomplished byan index mark placed on the web electrophotographically during the firstexposure and thus serves to trigger the flash tube in each successiveunit as the first image reaches a predetermined position with referenceto the proper image orientation in each successive unit.

The advantage of the register mark memory device of the presentinvention is the fact that the web need not be moved to accomplishregistration of the images, and in fact the web need not be present atall. Any shape or registering mark for obtaining registry of theregistration mark on the memory device with those of the transparencymay be used. The cross-lines parallel to the side edge of the web areused'for obtaining side registry and the cross-line which isperpendicular to the web edges may be used to obtain angular orientationof the pro jected image with the image projected from the transparency.

The register marks may be in any position on the transparency and theprinciples of the register mark memory device may be adopted so that theregistration marks of the memory device may be brought into alignmentwith the projected register marks. While the machine is adapted to printwebs of different widths, the movable arms and 82 may be so positionedwith respect to the further or closer to the projector 25 to repositionthe ski 19 according to actual web width. Necessary provisions may alsobe made for locating the gauge screws 55 for different web or severalwebs may be positioned in each station, one for each width web.

While the forms of apparatus herein described constitute preferredembodiments of the invention, it is to be understood that the inventionis not limited to these precise forms of apparatus, and that changes maybe made therein without departing from the scope of the invention whichis defined in the appended claims.

What is claimed is:

1. In a machine for exposing a light image onto a moving photoconductiveweb during passage of said web along a path through said machine, meansfor maintaining a section of said web in a predetermined, relativelyflat plane during exposure, an image-bearing transparency havingregister mark means thereon, a holder for mounting said transparency forexposure to said web, means located on the side of said holder remotefrom said web for projecting an image on to said web, means fordetecting the position of the side edge of said web and sensing anylateral deviation of said side edge from a normal position, meansresponsive to the movement of said detecting means for laterallyshifting said projected image in accordance with the lateral deviationof said web from a normal position, machine register mark indicia in theapproximate plane of said web, means for adjustably positioning theregister mark means of said transparency with respect to said registermark indicia, and said register mark indicia having a predeterminedrelationship with respect to the detecting means when in position todetect the side edge of the web in its normal path and with respect tosaid projection means.

2. The apparatus as set forth in claim 1 wherein said register markindicia and said transparency register mark means include side registermarks and additional register marks spaced from the side register marksare provided on both the machine and the transparency, wherein saidtransparency holder is adjustable angularly in its plane and toward andaway from the plane of said web to provide also for angular orientationand sizing of the transparency with respect to the web, and whereinmeans are provided for effecting said adjustments.

3. The apparatus as set forth in claim 1 wherein said detecting means ismovable and wherein said machine register mark indicia is operativelyconnected to said movable detecting means.

4. The apparatus as set forth in claim 2 wherein all of said machineregister marks are operatively connected to said movable detectingmeans.

5. The apparatus as set forth in claim 1 wherein said means formaintaining said web in a flat plane comprises a supporting table, andwherein said machine register mark indicia is mounted on said table.

6. The apparatus as set forth in claim 2 wherein said means formaintaining said web in a flat plane comprises a supporting table, andwherein all of said machine register marks are mounted on said table.

7. The apparatus as set forth in claim 1 wherein register mark meansincludes spaced register mark members carrying reference mark indiciathereon for movement in alignment with the register mark means projectedfrom said transparency, said means for maintaining said web in a flatplane including a supporting table, and support means for said movableregister mark members mounted on said supporting table in predeterminedrelationship with respect to the detecting means when in position todetect the side edge of the web in its normal path with respect to theprojection means.

8. The apparatus as set forth in claim 5 including means for maintainingsaid detecting means and lens system in predetermined positions withrespect to the side edge of the web in its normal path and with respectto said machine register mark indicia while said transparency holder isbeing adjusted to align the register mark on the transparency with themachine register mark indicia.

9. The apparatus as set forth in claim 8 wherein said register markindicia and said transparency register mark means include side registermarks and additional register marks spaced from the side register marksare provided on both the table and the transparency, wherein saidtransparency holder is also adjustable angularly in its plane and towardand away from said web to provide also for angular orientation andsizing of the transparency with respect to the web, and wherein meansare provided for effecting said adjustments.

it In a machine for successively exposing a plurality of light imagesonto a travelling web of imprint-receiving, photoconductive materialduring travel of said web along a path through successive exposingstations, each of said stations including means for maintaining said webin a predetermined, relatively flat plane as it passes through eachstation, an image-bearing transparency having register marks thereon, aholder for mounting said transparency for exposure to said web, means onthe side of the holder remote from said web for illuminating the webthrough said transparency at a predetermined time in the passage of saidweb through the station, an enlargement lens system located between thetransparency and said web, means for mounting said lens system formovement in opposite directions transversely of the web path while beingmaintained relatively parallel with the plane of said material, meansfor detecting the position of the side edge of said web and sensing anylateral deviation of said side edge from a normal position, meansinterconnecting t-he detectin means and said lens means for transmittingmovement of said detecting means to movement of said lens system and inproper ratio with respect to magnification of said transparency to saidweb whereby any side deviation. of said web from its path through agiven station will be compensated for by corresponding movement of saidlens means, register marks on said machine in the approximate plane ofsaid material, said machine register marks at one station being inpredetermined registration with corresponding register marks at otherstations, and means for adjusting each said transparency holder to alignthe transparency registration marks with their corresponding machineregistration marks, the lens means at each station being inpredetermined relationship with said machine registration marks duringalignment of said transparency register marks and said machine registermarks.

11. Apparatus as set forth in claim 10 wherein said machine registermarks in each station are opcratively connected to said detecting means.

12. The apparatus as set forth in claim 10 wherein said means at eachstation for maintaining the web in a flat plane comprises a supportingtable, and wherein said machine registcr marks are mounted on saidtable.

13. In a machine for exposing a light image onto a travelling web ofimprint-receiving, photoconductive material during passage of said webalong a path through said machine, means for maintaining a section ofsaid web in a predetermined, relatively fiat plane during exposure, animage-bearing transparency having a side register mark thereon, a holderfor mounting said transparency for exposure to said web, means forilluminating said web through said transparency, an enlargement lenslocated between the transparency and said web, means for detectinglateral deviation of said web from a normal path, means responsive to adeviation detection by said detecting means for effecting correspondinglateral movement of the transparency image with respect to said web inproper ratio relative to the magnification of said transparency to saidweb by said lens system, a machine side register mark in the approximateplane of said material,

and means for adjustably positioning said transparency holdertransversely of the normal path to align the transparency mark With saidmachine register marks, whereby an image placed upon the web in saidfiat plane will have a predetermined relationship relative to the normalpath of said web.

14. In a machine for successively exposing a plurality of light imagesonto a travelling Web of imprint-receiving, photoconductive materialduring travel of said web along a path through successive exposingstations, each of said stations including means for maintaining said webin a predetermined, relatively flat plane as it passes through eachstation, an image-bearing transparency having register marks thereon, aholder for mounting said trzmsparency for exposure to said web, means onthe side of the holder remote from said Web for illuminating the webthrough said transparency, lens means located between the transparencyand said Web, means for mounting said lens means for movement inopposite directions transversely of the Web pat-h while being maintainedrelatively parallel with the plane of said material, means for detectingthe position of the side edge of said Web and sensing any lateraldeviation of said side edge from a normal position, meansinterconnecting the detecting means and said lens means for transmittingmovement of said detecting means to movement of said lens means wherebyany side deviation of said Web from its path through a given stationwill be compensated for by corresponding movement of said lens means,stationary reference means in each exposure station oriented withrespect to the corresponding lens means whereby all said lens means maybe precision aligned along the path of web travel, said register markmemory means including movable indicia alignable with the register marksprojected from the transparency in the first exposure station, and saidregister mark memory means being receivable in each exposure in the samepredetermined orientation With the respective stationary reference meanswhereby the projected registration marks of the transparencies ofsubsequent stations may be aligned with said indica of said memorydevice to align all subsequent images With the image projected in saidfirst exposure station.

References Cited by the Examiner UNITED STATES PATENTS 8/1951 Waller etal. 8824 X 5/1965 Durlofsky 88-24

1. IN A MACHINE FOR EXPOSING A LIGHT IMAGE ONTO A MOVING PHOTOCONDUCTIVEWEB DURING PASSAGE OF SAID WEB ALONG A PATH THROUGH SAID MACHINE, MEANSFOR MAINTAINING A SECTION OF SAID WEB IN A PREDETERMINED, RELATIVELYFLAT PLANE DURING EXPOSURE, AN IMAGE-BEARING TRANSPARENCY HAVINGREGISTER MARK MEANS THEREON, A HOLDER FOR MOUNTING SAID TRANSPARENCY FOREXPOSURE TO SAID WEB, MEANS LOCATED ON THE SIDE OF SAID HOLDER REMOTEFROM SAID WEB FOR PROJECTING AN IMAGE ON TO SAID WEB, MEANS FORDETECTING THE POSITION OF THE SIDE EDGE OF SAID WEB AND SENSING ANYLATERAL DEVIATION OF SAID SIDE EDGE FROM A NORMAL POSITION, MEANSRESPONSIVE TO THE MOVEMENT OF SAID DETECTING MEANS FOR LATERALLYSHIFTING SAID PROJECTED IMAGE IN ACCORDANCE WITH THE LATERAL DEVIATIONOF SAID WEB FROM A NORMAL POSITION, MACHINE REGISTER MARK INDICIA IN THEAPPROXIMATE PLANE OF SAID WEB, MEANS FOR ADJUSTABLY POSITIONING THEREGISTER MARK MEANS OF SAID TRANSPARENCY WITH RESPECT TO SAID REGISTERMARK INDICIA, AND SAID REGISTER MARK INDICIA HAVING A PREDETERMINEDRELATIONSHIP WITH RESPECT TO THE DETECTING MEANS WHEN IN POSITION TODETECT THE SIDE EDGE OF THE WEB IN ITS NORMAL PATH AND WITH RESPECT TOSAID PROJECTION MEANS.